Description: Prairie dogs are small, stout, ground squirrels. The total length of an adult black-tailed prairie dog is approximately 14-17 inches. The weight of an individual ranges from approximately 1 to 3 pounds. Individual appearances within the species vary in mixed colors of brown, black, gray, and white. The black-tipped tail is characteristic.

Status: This species is a candidate for listing under the Endangered Species Act. As a candidate, the USFWS has information to support the listing of this species, but other species have higher priority for listing. Black-tailed prairie dog received a priority of 8 on a scale of 1-12 (1 being the highest priority).

Reasons for Current Status: Sylvatic plague has impacted the species throughout a significant portion of its range. Plague first occurred in black-tailed prairie dogs in Texas and Montana in the 1940's. Prairie dogs suffer nearly 100 percent mortality when exposed to plague. The spread of plague eastward in black-tailed prairie dog populations underscores the likelihood that unaffected areas may experience outbreaks. Approximately 66 percent of black-tailed prairie dog range in the United States is affected by sylvatic plague. More plague-free, suitable range occurs in South Dakota than in any other State within the historic range of the species.

Other factors currently impacting the species include chemical control and inadequate regulatory mechanisms. A factor which affected the species historically is the conversion of rangeland to cropland. Conversion of the native prairie to cropland has largely progressed across the species’ range from east to west, with the more intensive agricultural use in the eastern portion of the species’ range. The Black-footed Ferret Recovery Foundation evaluated the amount of habitat (grass/shrub lands) currently available to the species. In the plague-free portion of the species’ range (34 percent), less than 33 percent of the land is available to the species as non-cropland. Therefore, only approximately 10 percent of the black-tailed prairie dog range is both plague-free and currently suitable (i.e., not tilled).

Overutilization of prairie dogs is not considered a threat. Collection for the pet trade and recreational shooting may impact local populations, but will not cause significant rangewide population declines.

Reproduction and Development: The species is very social, living in population aggregations called colonies, towns, or villages. Historically, they generally occurred in large colonies that contained thousands of individuals, covered hundreds of thousands of acres, and extended for miles. Most existing colonies are much smaller. When unsuitable habitat such as a hill, tall vegetation, or a stream divides a prairie dog colony, the resulting subcolonies are called wards. Within colonies, prairie dogs live in territorial, harempolygamous family groups called coteries. Groups of colonies comprise a complex.

Black-tailed prairie dogs are not prolific in comparison to many other rodents. Several biological factors determine the reproductive potential of the species. Females usually do not breed until their second year and live 3-4 years. A common misconception is that prairie dogs produce multiple litters in a year. Female black-tailed prairie dogs produce a single litter, usually 4-5 pups, annually. Therefore, a female may produce from 0 to 20 young in its lifetime. In contrast, another female rodent, the meadow mouse (Microtus), can become pregnant at 3 weeks of age, have up to 17 litters in 1 year, and produce as many as 83 young before 1 year of age. Conversely, survival of young prairie dogs can be high in some circumstances, especially in low density populations where habitat resources are plentiful and repressive factors such as control or disease are not operative; although much lower rates of annual increase or even reductions in colony size can occur where vegetation hinders expansion or constricts existing colonies. For example, on Buffalo Gap National Grassland in South Dakota, during periods of drought and heavy stocking (both conducive to black-tailed prairie dog expansion), annual colony expansion rates approached 25 percent, while ungrazed areas showed expansion rates of 1-2 percent. Another misconception is that female black-tailed prairie dogs produce very large litters. Unfortunately, some older scientific literature furthers this perception. A large group of juveniles observed on the top of a single prairie dog mound does not indicate a very large litter, but may reflect communal nursing.

Range: Historically black-tailed prairie dogs were found throughout the plains from Canada to Mexico including the states of Arizona, Colorado, Kansas, Montana, Nebraska, New Mexico, North Dakota, Oklahoma, South Dakota, Texas, and Wyoming. The largest remnant populations currently are found in South Dakota, Wyoming, Montana, and Mexico.

Population Level: The remote and vast range of the prairie dog makes it difficult to estimate the number of prairie dogs. Occupied acreage for black-tailed prairie dogs is estimated to be approximately one to two million acres, based on available information.

Habitat: Black-tailed prairie dogs are residents of the short-grass and mixed-grass prairies of the United States.

Management Consideration: Rigorous monitoring, especially with regard of plague and the amount of occupied habitat, is an important requirement for successful management of the prairie dog. Meaningful regulation regarding chemical control could also contribute to improved management.

In South Dakota: The South Dakota Department of Game, Fish and Parks provided a statewide estimate (including tribal lands) of 142,000 acres (57,500 hectares) of black-tailed prairie dog occupied habitat at the Black-tailed Prairie Dog Conservation Team meeting in Las Cruces, NM on January 7-8, 2001. This estimate is similar to the Service estimate provided in the 12-month Finding of 147,000 acres (60,000 hectares). For specific sites, the National Park Service provided information regarding black-tailed prairie dog occupied habitat of 4,500 acres (1,800 hectares) at Badlands National Park. Turner Endangered Species personnel estimate 855 acres (346 hectares) of occupied habitat at Bad River Ranch. The Bureau of Land Management reports 210 acres (85 hectares) of occupied habitat on lands it manages in South Dakota. In general, populations of the black-tailed prairie dog in South Dakota appear to be stable. The species appears to be widely distributed throughout most of the species’ historic range in South Dakota. No recent changes in occupied habitat (approximately 100,000 acres / 40,500 hectares) have occurred on Tribal lands, where most of the occupied habitat currently exists in South Dakota.

U.S. Fish and Wildlife Service. 2002. Endangered and threatened wildlife and plants; Review of species that are candidates or proposed for listing as endangered or threatened; annual notice of findings on recycled petitions; annual description of progress on listing actions. Federal Register 67:40657-40679.